CN115837467A - Impact-resistant abrasion method for ultra-high water head impulse turbine bucket - Google Patents
Impact-resistant abrasion method for ultra-high water head impulse turbine bucket Download PDFInfo
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- CN115837467A CN115837467A CN202211572235.9A CN202211572235A CN115837467A CN 115837467 A CN115837467 A CN 115837467A CN 202211572235 A CN202211572235 A CN 202211572235A CN 115837467 A CN115837467 A CN 115837467A
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 90
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- 238000005299 abrasion Methods 0.000 title claims abstract description 14
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/20—Hydro energy
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- Coating By Spraying Or Casting (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
The invention discloses an impact-resistant abrasion method for a bucket of an ultra-high water head impulse turbine, which comprises the following steps: fixing a set of hard alloy lining on the whole surface of the inner wall of the water bucket in a semi-elastic contact connection mode, wherein the semi-elastic contact connection mode means that the hard alloy lining is adhered to the water bucket through structural glue to absorb and buffer different elastic micro-deformation between the lining and the water bucket, and the edge of the hard alloy lining tightly presses the lining and the water bucket through a fastener to prevent the hard alloy lining from moving; in addition, the hard alloy protective coating can be prepared on the outer wall of the water bucket and the surface of the fastener by adopting a supersonic flame thermal spraying technology. The protection of the inner wall of the water bucket adopts the hard alloy lining to replace the coating, the thickness of the hard alloy lining can reach the thickness which cannot be reached by the coating, and simultaneously, the hard alloy lining is adopted, so that the impact wear resistance of the inner wall of the water bucket is greatly enhanced, and the service life of the water bucket is greatly prolonged.
Description
Technical Field
The invention relates to the field of water conservancy surface technology and engineering, in particular to an impact-resistant abrasion method for a bucket of an ultrahigh water head impulse type water turbine.
Background
With the continuous progress of the technology, the application of the impulse turbine in a high-head hydropower station is increasingly wide. However, the bucket life of the impulse turbine is short, and especially in some hydropower stations with ultrahigh water heads of more than one thousand meters, the bucket is eroded seriously. Through investigation, engineers have the ability to improve erosion and wear of impulse turbines and prolong the life of the turbines by preparing highly wear-resistant cermet coatings or polyurethane coatings on the surfaces of buckets. However, the above coatings have limited effectiveness from a practical use feedback perspective. Because the impact force from the nozzle to the bucket is very great under the condition of ultrahigh water head, and the sediment in the water can cause very great impact and plowing action on the inner wall of the bucket. The common WC series hard alloy coatings are generally prepared by a supersonic flame spraying method, the coating thickness prepared by the method is not too thick, is usually within the range of 200-400 microns, and has good wear-resistant and corrosion-resistant effects when applied to mixed-flow water turbines, axial-flow Kaplan water turbines and some low-head impulse water turbines. However, when the ceramic coating is applied to an impulse turbine with an ultrahigh water head, particularly the inner wall of a bucket, the thin and brittle metal ceramic coating can be easily crushed by impact and fall off from a matrix. The polyurethane coating has good elasticity, the sand prevention particles have good vertical impact capability, but the sand and sand prevention cutting capability is weaker, and the polyurethane coating is easy to peel off due to the strong action because the bonding strength with the matrix is lower. Therefore, an effective solution is urgently needed for the impact and abrasion resistance problem of the impulse turbine bucket with the ultrahigh water head of more than kilometers.
Disclosure of Invention
The invention aims to solve the problems of corrosion resistance and abrasion resistance of an ultra-high water head impulse turbine bucket, and provides an impact-resistant abrasion method of the ultra-high water head impulse turbine bucket. In addition, the outer wall of the water bucket and the surface of the fastener are provided with the hard alloy protective coating by adopting a supersonic flame thermal spraying technology.
The technical scheme adopted by the invention is as follows:
a set of hard alloy bushings is fixed on the whole surface of the inner wall of a bucket in a semi-elastic contact connection mode, wherein the semi-elastic contact connection mode refers to that the hard alloy bushings are adhered to the bucket through structural glue to absorb and buffer different elastic micro-deformation between the bushings and the bucket, and the edges of the hard alloy bushings tightly press the bushings and the bucket through fasteners to prevent the hard alloy bushings from moving.
Further, a hard alloy protective coating is prepared on the outer wall of the water bucket and the surface of the fastener by adopting a supersonic flame thermal spraying technology.
The manufacturing technology of the hard alloy bushing selects a vacuum sintering technology to obtain the characteristics of high density, low impurity and high strength. The hard alloy mixed powder is firstly pressed under high pressure to prepare a blank with a proper size of the shape of the inner wall of the water bucket, and the size of the hard alloy lining is ensured to be consistent with that of the water bucket of the water turbine after vacuum sintering. Then, carrying out a vacuum sintering process, which comprises the following three processes: pre-sintering, high-temperature sintering and cooling. In the pre-burning stage, when the vacuum degree is lower than 10Pa, the temperature starts to rise, and when the temperature reaches a proper temperature, the temperature is kept for a certain time to ensure that impurities are discharged. The temperature is generally between 250 and 600 ℃, and the heat preservation time is set according to the amount of the forming agent. The heat preservation time can be in the interval of 12 h-24 h according to the size of a common impulse turbine bucket. In the high-temperature sintering stage, the temperature is selected within a range of 1300-1500 ℃, the heat preservation time is selected within a range of 2-10 h, and the temperature is selected according to the material and the size of the hard alloy lining. Inert gas such as argon is introduced in the cooling stage to accelerate cooling, and meanwhile, the compactness of the hard alloy lining can be improved.
Furthermore, the material of the hard alloy lining is selected from a formula combination of WC-Co-inhibitor-wetting agent-rare earth, and the grain diameter of each component powder is superfine and is less than 1 micron. The composite formula combination is preferably as follows: WC-Co-VC-TaC-La 2 O 3 ，WC-Co-Cr 2 C 3 -TiC-Mo-CeO 2 ，WC-Co-NbC-Cr-La 2 O 3 (ii) a The formula of the material enables the hard alloy lining to have finer grains, higher strength, higher compactness and higher toughness, and is very suitable for the working environment of the impulse turbine bucket.
Further, the cemented carbide liner thickness can be made much thicker, much thicker than cemented carbide coatings made by supersonic flame thermal spraying, which are typically below 0.4mm thick. Under the strong washing of silt, the thin hard alloy coating can be easily peeled off from the substrate because of the different deformation coefficients of the coating and the substrate and the low bonding strength (generally about 70 MPa) of the coating and the substrate. The thick high-strength hard alloy lining is more resistant to sand erosion and abrasion, and can not be broken due to different deformation coefficients of the hard alloy lining material and the water bucket material due to the semi-elastic contact connection mode of the thick high-strength hard alloy lining and the water bucket. The semi-elastic contact connection mode means that the hard alloy lining and the water bucket are adhered through the structural adhesive on one hand, the structural adhesive can play a role in absorbing and buffering different elastic micro-deformation between the hard alloy lining and the water bucket, and the hard alloy lining is prevented from cracking and breaking. On the other hand, the hard alloy lining is further prevented from moving by pressing the edge of the hard alloy lining through the fastener.
The fastener comprises two parts, wherein one part is a fixed part and can be welded and fixed on the water bucket along the upper surface of the water bucket, a through hole can be drilled in the middle, the other part is a movable part, a threaded hole (not a through hole) can be drilled in the movable part, the two parts are fastened through a fastening bolt, and the hard alloy lining is tightly pressed on the water bucket.
The technological process of protecting the bucket of the impulse turbine comprises the following steps:
1) Welding the fixed part of the fastener on the upper surface of the impulse turbine bucket;
2) Cleaning greasy dirt on the inner wall, the outer wall and other surfaces of the impulse turbine by using a cleaning agent, then blasting sand on the surfaces by using white corundum, and ensuring that the roughness of the surface of a bucket after sand blasting and coarsening reaches more than Ra 10.
3) The high-strength structural adhesive is coated on the inner wall of the bucket, for example, the high-strength acrylate structural adhesive can be adopted, has the characteristics of acid and alkali resistance, water and oil medium corrosion resistance, impact resistance, large working temperature range (-30-150 ℃), high bonding strength of 70Mpa and the like, is very suitable for adhesion between a WC hard alloy lining and the steel bucket, and is also very suitable for the working environment of the bucket of the impulse water turbine.
4) And tightly attaching the hard alloy lining to the inner wall of the bucket of the impulse turbine, fastening the movable part of the fastener through a bolt, tightly pressing the hard alloy lining, and waiting for curing for more than 24 hours.
5) For other flow passing areas of the water bucket where the supersonic flame thermal spraying of the hard alloy coating is needed, the WC-Co series hard alloy coating is prepared by the supersonic flame thermal spraying technology.
In addition, the invention also provides an impulse turbine bucket capable of working under an ultrahigh water head, which comprises a bucket body, a hard alloy lining and a fastening piece; the fastener comprises a fixed part and a movable part; the carbide bush covers whole water bucket body inner wall, and is glued through the structure with the water bucket inner wall and is connected, and mounting welding water bucket body edge, moving part compress tightly carbide bush and water bucket edge and pass through bolt and mounting fastening connection, and other regions and the fastener surface that overflow at the water bucket are prepared with carbide protective coating.
The invention has the beneficial effects that:
the protection of the inner wall of the water bucket adopts the hard alloy lining to replace the coating, the thickness of the hard alloy lining can reach the thickness which cannot be reached by the coating, and meanwhile, the hard alloy lining adopts a new formula, and the hard alloy lining greatly enhance the impact wear resistance of the hard alloy lining and the hard alloy lining, so that the service life of the inner wall of the water bucket is greatly prolonged. Meanwhile, in the area of the bucket indirectly impacted by the silt, the WC-Co series hard alloy coatings are prepared by adopting a supersonic flame thermal spraying technology, so that the service life of the whole bucket of the impulse turbine is greatly prolonged. Compared with the common water turbine 0Cr13Ni5Mo stainless steel, the silt-resistant abrasion resistance of the common WC-Co series hard alloy coating is improved by 3-5 times, and compared with the traditional supersonic flame thermal spraying WC-Co series hard alloy coating, the lifting of the inner wall of the bucket by the hard alloy lining method provided by the invention has the advantages that the silt-resistant impact abrasion resistance is greatly improved, and the practical application effect is achieved: compared with the traditional method for spraying the coating on the bucket, the service life of the bucket is half a year to one year, and the service life of the bucket of the high-head impulse turbine can be more than 5 years by the method provided by the invention.
Drawings
Fig. 1 is a schematic view of the impulse turbine bucket of the present invention.
In the figure: 1-a hard alloy lining, 2-a water bucket base body, 3-a fixed part in a fastener, 4-a movable part in the fastener, 5-a welding seam and 6-WC hard alloy coating.
Detailed Description
The following detailed description is further described in conjunction with the accompanying drawings
Referring to fig. 1, a schematic diagram of an impact erosion resisting method of an ultra-high head impulse turbine bucket is shown.
Example 1
Composition of the cemented carbide insert 1: WC-Co-VC-TaC-La 2 O 3 Wherein Co 9% by weight, particle size 0.5 to 1 μm, VC 10% by weight, particle size 0.5 to 1 μm, taC 7% by weight, particle size 0.5 to 1 μm, la 2 O 3 1 wt%, particle size 0.5-1 μm, balance WC, particle size 1-2 μm.
The manufacturing technology of the hard alloy lining 1 selects a vacuum sintering technology to obtain the characteristics of high density, low impurity and high strength. The hard alloy mixed powder is firstly pressed under high pressure to form a blank with a proper size of the shape of the inner wall of the bucket, and the size of the hard alloy lining 1 is ensured to be matched with the size of the inner wall of the bucket base body 2 of the water turbine after vacuum sintering. Then carrying out a vacuum sintering process, which comprises the following three processes: pre-sintering, high-temperature sintering and cooling. And in the pre-sintering stage, when the vacuum degree is lower than 1Pa, the temperature is increased, and when the temperature reaches 350 ℃, the temperature is maintained for 10 hours to ensure that impurities are discharged. And in the high-temperature sintering stage, the temperature is kept at 1400 ℃ for 5 hours. Argon is introduced in the cooling stage, the pressure is 3MPa, the cooling is accelerated, and meanwhile, the compactness of the hard alloy lining can be improved. The average thickness of the hard alloy lining is made to be 5mm
A through hole is drilled in the fixing piece 4 of the fastening piece and welded at the outlet of the upper surface of the water bucket base body 2, the position of a welding seam 5 can be selected at the welding joint, and a plurality of fastening pieces 4 can be arranged around the upper plane of the water bucket.
A threaded hole which is not a through hole is drilled in the movable part 3 of the fastener, one end of the threaded hole is tightly attached to the hard alloy bushing 1, and the other end of the threaded hole is tightly connected with the fixed part 4 of the fastener through a fastening bolt to tightly press the hard alloy bushing 1.
WC cemented carbide coating 6, in a given area by HVOF (high velocity oxygen gas) technique: the surface of the outer wall of the water bucket base body 2, the fixed part 4 in the fastener and the movable part 3 in the fastener are prepared by spraying, and the spraying material can select a WC-Co series hard alloy coating powder formula which is mature in market, such as WC-10Co-4Cr powder.
The technological process of protecting the bucket of the impulse turbine comprises the following steps:
1. welding a fixing piece 4 in the fastening piece on the upper surface of the impulse turbine bucket base body 2;
2. cleaning greasy dirt on the inner wall, the outer wall and other surfaces of the water bucket base body 2 by using a cleaning agent, then carrying out sand blasting on the surfaces by using white corundum, and enabling the roughness of the water bucket surface after sand blasting coarsening to reach more than Ra 10.
3. The high-strength acrylate structural adhesive has the characteristics of acid and alkali resistance, water and oil medium corrosion resistance, impact resistance, large working temperature range (-30-150 ℃), high bonding strength of 70Mpa and the like, is very suitable for adhesion between the WC hard alloy lining 1 and the steel bucket base body 2, and is also very suitable for the working environment of the impulse turbine bucket.
4. The hard alloy lining 1 is tightly attached to the inner wall of the impulse turbine bucket base body 2, the moving part 3 in the fastener is fastened through the bolt, the hard alloy lining 1 is pressed tightly, and the solidification is waited for more than 24 hours.
5. For other flow passing areas of the water bucket where the supersonic flame thermal spraying of the hard alloy coating is needed, the WC-Co series hard alloy coating is prepared by the supersonic flame thermal spraying technology.
6. After the spraying is finished, the paint can be put into use. And when the next bucket maintenance time is up, the hard alloy lining 1 can be replaced quickly, so that the maintenance time and cost of the water turbine are greatly saved. The abrasion and erosion effects of the hard alloy coating in the indirect erosion area of the bucket of the impulse turbine are relatively small, so that the coating only needs to be prepared in the indirect erosion area of the bucket after the hard alloy lining 1 is replaced for many times.
Example 2
Composition of the cemented carbide insert 1: WC-Co-Cr 2 C 3 -TiC-Mo-CeO 2 Wherein Co 10% by weight, particle size 0.5 to 1 μm, cr 2 C 3 12% by weight, particle size 0.5 to 1 μm, tiC 4% by weight, particle size 0.5 to 1 μm, mo 5% by weight, particle size 0.5 to 1 μm, ceO 2 0.8 wt%, particle size 0.5-1 μm, balance WC, particle size 1-2 μm.
The manufacturing technology of the hard alloy lining 1 selects a vacuum sintering technology to obtain the characteristics of high density, low impurity and high strength. The hard alloy mixed powder is firstly pressed under high pressure to prepare a blank with a proper size of the shape of the inner wall of the water bucket, and the size of the hard alloy lining 1 is ensured to be consistent with the size of the inner wall of the water bucket base body 2 of the water turbine after vacuum sintering. Then carrying out a vacuum sintering process, which comprises the following three processes: pre-sintering, high-temperature sintering and cooling. And in the pre-sintering stage, when the vacuum degree is lower than 0.2Pa, the temperature is increased, and when the temperature reaches 430 ℃, the temperature is maintained for 15 hours, so that impurities are discharged. And in the high-temperature sintering stage, the temperature is kept at 1450 ℃ for 6 hours. Argon is introduced in the cooling stage, the pressure is 4MPa, the cooling is accelerated, and meanwhile, the compactness of the hard alloy lining can be improved. The average thickness of the cemented carbide lining is made 8mm.
A through hole is drilled in a fixing piece 4 of the fastening piece and welded at an outlet of the upper surface of the water bucket base body 2, the position of a welding seam 5 can be selected at the welding joint, and the fastening pieces 4 are distributed around the upper plane of the water bucket in a surrounding mode.
A threaded hole which is not a through hole is drilled in the movable part 3 of the fastener, one end of the threaded hole is tightly attached to the hard alloy bushing 1, and the other end of the threaded hole is tightly connected with the fixed part 4 of the fastener through a fastening bolt to tightly press the hard alloy bushing 1.
WC cemented carbide coating 6, in a given area by HVOF (high velocity oxygen gas) technique: the surface of the outer wall of the water bucket base body 2, the fixed part 4 in the fastener and the movable part 3 in the fastener are prepared by spraying, and the spraying material can be selected from powder formulations which are well-established in the market, such as WC-10Co-4Cr powder.
The technological process of protecting the bucket of the impulse turbine comprises the following steps:
1. welding a fixing piece 4 in the fastening piece on the upper surface of the impulse turbine bucket base body 2;
2. and cleaning oil stains on the inner wall, the outer wall and other surfaces of the water bucket base body 2 by using a cleaning agent, and then carrying out sand blasting on the surfaces by using white corundum, wherein the roughness of the surface of the water bucket after sand blasting and coarsening reaches more than Ra 10.
3. The high-strength silicone structural adhesive has the characteristics of acid and alkali resistance, water and oil medium corrosion resistance, impact resistance, large working temperature range, bonding strength of 60Mpa and the like, is very suitable for adhesion between the WC hard alloy lining 1 and the steel bucket base body 2, and is also very suitable for the working environment of the impulse turbine bucket.
4. The hard alloy lining 1 is tightly attached to the inner wall of the impulse turbine bucket base body 2, the moving part 3 in the fastener is fastened through the bolt, the hard alloy lining 1 is pressed tightly, and the solidification is waited for more than 24 hours.
5. For other flow passing areas of the water bucket where the supersonic flame thermal spraying of the hard alloy coating is needed, the WC-Co series hard alloy coating is prepared by the supersonic flame thermal spraying technology.
6. After the spraying is finished, the paint can be put into use. And when the next bucket maintenance time is up, the hard alloy lining 1 can be replaced quickly, so that the maintenance time and cost of the water turbine are greatly saved. The abrasion and erosion effects of the hard alloy coating in the indirect erosion area of the bucket of the impulse turbine are relatively small, so that the coating only needs to be prepared in the indirect erosion area of the bucket after the hard alloy lining 1 is replaced for many times.
Example 3
Composition of the cemented carbide insert 1: WC-Co-NbC-Cr-La 2 O 3 Wherein Co 12% by weight, particle size 0.5 to 1 μm, nbC 8% by weight, particle size 0.5 to 1 μm, cr 7% by weight, particle size 0.5 to 1 μm, la 2 O 3 1.2% by weight, particle size 0.5 to 1 μm, balance WC, particle size 1 to 2 μm.
The manufacturing technology of the hard alloy lining 1 selects a vacuum sintering technology to obtain the characteristics of high compactness, low impurities and high strength. The hard alloy mixed powder is firstly pressed under high pressure to form a blank with a proper size of the shape of the inner wall of the bucket, and the size of the hard alloy lining 1 is ensured to be matched with the size of the inner wall of the bucket base body 2 of the water turbine after vacuum sintering. Then carrying out a vacuum sintering process, which comprises the following three processes: pre-sintering, high-temperature sintering and cooling. And in the pre-sintering stage, when the vacuum degree is lower than 5Pa, the temperature is increased, and when the temperature reaches 500 ℃, the temperature is maintained for 10 hours to ensure that impurities are discharged. And in the high-temperature sintering stage, the temperature is kept at 1380 ℃ for 7 hours. Argon is introduced in the cooling stage, the pressure is 5MPa, the cooling is accelerated, and meanwhile, the compactness of the hard alloy lining can be improved. The average thickness of the cemented carbide lining is made to be 10mm.
A through hole is drilled in a fixing piece 4 of the fastening piece and welded at an outlet of the upper surface of the water bucket base body 2, the position of a welding seam 5 can be selected at the welding joint, and the fastening pieces 4 are distributed around the upper plane of the water bucket in a surrounding mode.
A threaded hole which is not a through hole is drilled in the movable part 3 of the fastener, one end of the threaded hole is tightly attached to the hard alloy bushing 1, and the other end of the threaded hole is tightly connected with the fixed part 4 of the fastener through a fastening bolt to tightly press the hard alloy bushing 1.
WC cemented carbide coating 6, in a given area by HVOF (high velocity oxygen gas) technique: the surface of the outer wall of the water bucket base body 2, the fixed part 4 in the fastener and the movable part 3 in the fastener are prepared by spraying, and the spraying material can be selected from powder formulations which are well-established in the market, such as WC-10Co-4Cr powder.
The technological process of protecting the bucket of the impulse turbine comprises the following steps:
1. welding a fixing piece 4 in the fastening piece on the upper surface of the impulse turbine bucket base body 2;
2. cleaning greasy dirt on the inner wall, the outer wall and other surfaces of the water bucket base body 2 by using a cleaning agent, then carrying out sand blasting on the surfaces by using white corundum, and enabling the roughness of the water bucket surface after sand blasting coarsening to reach more than Ra 10.
3. The high-strength epoxy resin structural adhesive has the characteristics of acid and alkali resistance, water and oil medium corrosion resistance, impact resistance, large working temperature range, bonding strength of 30Mpa and the like, is very suitable for adhesion between the WC hard alloy bushing 1 and the steel bucket base body 2, and is also very suitable for the working environment of the impulse turbine bucket.
4. The hard alloy lining 1 is tightly attached to the inner wall of the impulse turbine bucket base body 2, the moving part 3 in the fastener is fastened through the bolt, the hard alloy lining 1 is pressed tightly, and the solidification is waited for more than 48 hours.
5. For other flow passing areas of the water bucket where the supersonic flame thermal spraying of the hard alloy coating is needed, the WC-Co series hard alloy coating is prepared by the supersonic flame thermal spraying technology.
6. After the spraying is finished, the paint can be put into use. When the next time of bucket maintenance, can replace carbide bush 1 fast, practiced thrift the maintenance duration and the cost of hydraulic turbine greatly. The abrasion and erosion effects of the hard alloy coating in the indirect erosion area of the bucket of the impulse turbine are small, so that the coating only needs to be prepared again in the indirect erosion area of the bucket after the hard alloy lining 1 is replaced for many times.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications, equivalent variations and modifications made according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.
Claims (7)
1. An impact abrasion resisting method for a bucket of an ultra-high head impulse turbine is characterized by comprising the following steps: the inner wall full surface of the water bucket is fixed with a set of hard alloy bushing in a semi-elastic contact connection mode, the semi-elastic contact connection mode means that the hard alloy bushing and the water bucket are adhered through structural glue to absorb and buffer different elastic micro-deformation between the bushing and the water bucket, and the edge of the hard alloy bushing compresses the bushing and the water bucket through a fastener to prevent the hard alloy bushing from moving.
2. The method for resisting impact erosion of the ultra-high head impulse turbine bucket according to claim 1, wherein the hard alloy protective coating is prepared on the outer wall of the bucket and the surface of the fastener by a supersonic flame thermal spraying technology.
3. The method for resisting impact erosion of the bucket of the ultra-high head impulse turbine as claimed in claim 1, wherein the hard alloy lining is formed by firstly pressing hard alloy mixed powder under high pressure to form a blank which is sintered and matched with the shape and the size of the inner wall of the bucket, and performing vacuum sintering, and comprises the following steps: presintering, high-temperature sintering and cooling; in the pre-sintering stage, when the vacuum degree is lower than 10Pa, the temperature is raised to 250-600 ℃, the temperature is kept for 12-24 h, the temperature in the high-temperature sintering stage is 1300-1500 ℃, the temperature keeping time is 2-10 h, inert gas is introduced in the cooling stage to accelerate cooling, and meanwhile, the compactness of the hard alloy lining is increased.
4. The method for resisting impact erosion of the ultra-high head impulse turbine bucket of claim 1, wherein the material of the cemented carbide lining is a formula combination of WC-Co-inhibitor-wetting agent-rare earth, and the particle size of each component powder is less than 1 micron.
5. The method for resisting impact erosion of the bucket of the ultra-high head impulse turbine as claimed in claim 1, wherein the fastening member comprises two parts, one part is a fixed member welded and fixed on the edge of the bucket, the other part is a movable member, the movable member presses the hard alloy lining on the bucket, and the two parts are fastened through a fastening bolt.
6. The method for resisting impact erosion of an ultra-high head impulse turbine bucket according to claim 5, wherein the process for protecting the impulse turbine bucket comprises the following steps:
1) Welding a fixing piece of a fastening piece on the upper surface of a bucket of the impulse water turbine;
2) Cleaning oil stains on the inner wall, the outer wall and other surfaces of the impulse turbine by using a cleaning agent, and then blasting sand on the cleaned surface by using white corundum, wherein the roughness of the surface of a bucket after sand blasting and coarsening reaches more than Ra 10;
3) Coating high-strength structural adhesive on the inner wall of the water bucket;
4) Tightly attaching the hard alloy lining to the inner wall of a bucket of the impulse turbine, tightly pressing the hard alloy lining and the bucket by a moving part of a fastener, fastening the moving part and a fixing part through bolts, and waiting for curing for more than 24 hours;
5) And preparing the WC-Co hard alloy coating on other overflowing areas of the water bucket and the surface of the fastener by a supersonic flame thermal spraying technology.
7. An ultra-high water head impulse turbine bucket is characterized by comprising a bucket body, a hard alloy lining and a fastening piece; the fastener comprises a fixed part and a movable part; the carbide bush covers whole water bucket body inner wall, and is glued through the structure with the water bucket inner wall and is connected, and mounting welding water bucket body edge, moving part compress tightly carbide bush and water bucket edge and pass through bolt and mounting fastening connection, and other regions and the fastener surface that overflow at the water bucket are prepared with carbide protective coating.
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